Mick and Mairead Philpott shared their home with Mick's girlfriend and 11 children in a relationship which can be described as polyamorous.
Why do people live with more than one sexual partner, and are there problems that can arise with these relationships?
Mairead Philpott said she was initially hurt by her husband's relationship with Lisa Willis, but went along with it because she was scared of losing her family and home.
While there is little research on polyamory, research on polygamy - where people marry multiple partners - suggests that some women can feel pressured into consenting.
Dr Thom Brooks, who has researched polygamy and polyamory, said a lack of consent by women was one of the most significant problems.
"The two are practised very similarly and [are] almost always a relationship of one man with two or three women, with the man at its centre," said Dr Brooks, of Durham University.
But marriage and family therapist Dossie Easton, who has been in polyamorous relationships, said they were different in nature to polygamous marriages.
"Polyamory does not follow the rather strict forms of marriage and gender in relationships that are found in many polygamous cultures, [such] as in Islam and Mormon[ism]," she said.
It is difficult to estimate how many people in the UK are polyamorous, as some keep their relationships a secret.
But Ms Easton believes more people are experimenting as polyamory becomes less frowned upon, in the same way that same-sex relationships are now widely accepted.
"Polyamory has come out of the closet, and thus more people feel free to try what had been very forbidden," she said.
"Nowadays you don't have to be a hippy or a rebel to explore an expanded sex life." ...